Alert archive / Louisiana / Mesoscale Discussions in 2011
Mesoscale Discussion 207
The Storm Prediction Center issued this mesoscale discussion at Mar 8, 2011, 5:46 PM CST for 39 parishes in Louisiana; 25 counties in Mississippi. It was in force for 59 min.
The area
The outline as issued.
The facts
- Issued
- Mar 8, 2011, 5:46 PM CST (23:46 UTC)
- Expired
- Mar 8, 2011, 6:45 PM CST
- In force
- 59 min
- Issued by
- the Storm Prediction Center
All 64 counties
Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Livingston Parish, LA, Madison Parish, LA, Natchitoches Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Vernon Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Hancock County, MS, Hinds County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Warren County, MS, Wilkinson County, MS
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Lake Charles Mun, LA (KLCH), launched 12:00Z, 11.8 hours before the alert went out and 188 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 51 J/kg
- Mixed-layer CIN
- -36 J/kg
- Mixed-layer LCL
- 513 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 276 m²/s²
- 0-3 km storm-relative helicity
- 464 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted, in the capitals the NWS used until 2016.
064 ACUS11 KWNS 082346 SWOMCD SPC MCD 082346 MSZ000-LAZ000-TXZ000-090045- MESOSCALE DISCUSSION 0207 NWS STORM PREDICTION CENTER NORMAN OK 0546 PM CST TUE MAR 08 2011 AREAS AFFECTED...SERN TX...LA...SRN MS CONCERNING...TORNADO WATCH 42... VALID 082346Z - 090045Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 42 CONTINUES. ...TORNADO THREAT CONTINUES ACROSS MUCH OF LA AND SRN MS. A LONGER TERM THREAT WILL NECESSITATE A NEW TORNADO WATCH BETWEEN 01-02Z... WARM SECTOR IS GRADUALLY SPREADING NORTH ACROSS WW42 WITH 70F SFC DEW POINTS NOTED SOUTH OF WARM FRONT. THIS WARM FRONT HAS SERVED TO FOCUS A FAIRLY LARGE MCS WITH A SOMEWHAT DISORGANIZED MCV LIFTING ENEWD AT ROUGHLY 25KT OVER MARION COUNTY MS. NUMEROUS CELLULAR UPDRAFTS AND ISOLATED EMBEDDED SUPERCELLS HAVE EVOLVED WITHIN THE LARGER THUNDERSTORM COMPLEX. THIS ACTIVITY IS EXPECTED TO GRADUALLY SHIFT EAST OF THE WATCH ACROSS SRN MS WHERE BOUNDARY LAYER HAS YET TO RECOVER SIGNIFICANTLY. WITH TIME THE WARM FRONT SHOULD GRADUALLY LIFT NWD ALLOWING MARITIME TROPICAL AIRMASS TO ENHANCE THE PROSPECT FOR SFC-BASED SUPERCELLS. UPSTREAM...NEW UPDRAFTS HAVE RECENTLY DEVELOPED ALONG THE LOWER SABINE RIVER REGION AND THESE STORMS ARE GRADUALLY MATURING AS THEY SPREAD NEWD INTO WRN PORTIONS OF WW42. THIS AREA IS NOT PARTICULARLY FOCUSED/CONVERGENT BUT AIRMASS IS VERY MOIST AND SUFFICIENTLY SHEARED FOR A CONTINUED TORNADO THREAT. ..DARROW.. 03/08/2011 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MOB...JAN...LIX...LCH...SHV... LAT...LON 32109365 32708915 30238915 29649364 32109365
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 8, 9:52 AM CST | Mesoscale Discussion | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Bienville and 38 more | 53 min |
| Mar 8, 12:54 PM CST | Mesoscale Discussion | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 46 more | 36 min |
| Mar 8, 1:08 PM CST | Tornado Watch | SPC | Acadia, Allen, Ascension, Avoyelles, Beauregard, Calcasieu and 33 more | 9 hr |
Nearby
Mesoscale Discussions in Louisiana, 2011Mesoscale Discussions in Mississippi, 2011Every mesoscale discussion in 2011
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.